scholarly journals On the Structure and Evolution of a Polar Crown Prominence/Filament System

2014 ◽  
pp. 349-369
Author(s):  
N. K. Panesar ◽  
D. E. Innes ◽  
D. J. Schmit ◽  
S. K. Tiwari
Keyword(s):  
Filament System

Characterization of a novel filament system in goldfish xanthophores

1997 ◽  
Vol 36 (3) ◽  
pp. 216-227 ◽  
Author(s):  
Seu-Mei Wang ◽  
Jin-Shan Chen ◽  
Tsorng-Harn Fong ◽  
Shu-Yuan Hsu ◽  
Soo-Siang Lim
Keyword(s):  
Filament System

Biophysics of flagellar motility

1979 ◽  
Vol 12 (2) ◽  
pp. 103-180 ◽  
Author(s):  
Jacob J. Blum ◽  
Michael Hines
Keyword(s):  
Viscous Medium ◽  
Hydrodynamic Interactions ◽  
Eukaryotic Cells ◽  
Flagellar Motility ◽  
Muscle System ◽  
Structured Products ◽  
Filament System ◽  
Complex Organization ◽  
Propagating Waves ◽  
Sudden Appearance

One feature characterizing the transition from prokaryote to eukaryote is the ‘sudden’ appearance of centrioles and their highly structured products, the typical eukaryotic flagella and cilia. These mechanochemical systems appear as fully developed machines, containing some 200 diffierent proteins (Luck et al. 1978) arranged in a remarkably complex organization which has undergone little modification since the advent of the first eukaryotic cells. It is now well established (see, for example, Satir, 1974) that ciliary and flagellar motility is based on a sliding filament mechanism that superficially resembles the far more extensively studied sliding filament system of striated skeletal muscle.The flagellar system, however, appears to be much more complex than the muscle system, because it does not ‘merely’ shorten and generate force, but develops propagating waves and exerts its effects via hydrodynamic interactions with a viscous medium.

The presence or absence of a vimentin-type intermediate filament network affects the shape of the nucleus in human SW-13 cells

1994 ◽  
Vol 107 (6) ◽  
pp. 1593-1607 ◽  
Author(s):  
A.J. Sarria ◽  
J.G. Lieber ◽  
S.K. Nordeen ◽  
R.M. Evans
Keyword(s):  
Electron Microscopy ◽  
Intermediate Filament ◽  
Nuclear Morphology ◽  
Intermediate Filament Protein ◽  
Mosaic Pattern ◽  
Expression Plasmid ◽  
Vimentin Expression ◽  
Filament System ◽  
Filament Protein ◽  
Filament Network

Human SW-13 cells express the intermediate filament protein vimentin in a mosaic pattern (Hedberg, K. K. and Chen, L. B. (1986). Exp. Cell Res. 163, 509–517). We have isolated SW-13 clones that do (vim+) or do not (vim-) synthesize vimentin as analyzed using anti-intermediate filament immunofluorescence, electron microscopy and two-dimensional gel analysis of detergent-extracted preparations. Vimentin is the only cytoplasmic intermediate filament protein present in the vim+ cells, and the vim- cells do not contain any detectable cytoplasmic intermediate filament system. The presence or absence of intermediate filaments did not observably affect the distribution of mitochondria, endoplasmic reticulum, microtubules or actin stress fibers when these structures were visualized by fluorescence microscopy. However, electron microscopy and anti-lamin A/C immunofluorescence studies showed that nuclear morphology in vim- cells was frequently characterized by large folds or invaginations, while vim+ cells had a more regular or smooth nuclear shape. When vim- cells were transfected with a mouse vimentin expression plasmid, the synthesis of a mouse vimentin filament network restored the smooth nuclear morphology characteristic of vim+ cells. Conversely, when vim+ cells were transfected with a carboxy-terminally truncated mutant vimentin, expression of the mutant protein disrupted the organization of the endogenous vimentin filaments and resulted in nuclei with a prominently invaginated morphology. These results indicated that in SW-13 cells the vimentin filament system affects the shape of the nucleus.

Two Energy-release Processes Observed in the Eruption of a Confined Filament System

2018 ◽  
Vol 130 (994) ◽  
pp. 124401 ◽  
Author(s):  
Hongbo Li ◽  
Yu Liu ◽  
Jihong Liu ◽  
A. Elmhamdi ◽  
A.-S. Kordi
Keyword(s):  
Energy Release ◽  
Filament System ◽  
Release Processes

Changes of the actin filament system in the green algaMicrasterias denticulata induced by different cytoskeleton inhibitors

PROTOPLASMA ◽  
2000 ◽  
Vol 212 (3-4) ◽  
pp. 206-216 ◽  
Author(s):  
M. Pfl�gl-Haill ◽  
L. Vidali ◽  
J. W. Vos ◽  
P. K. Hepler ◽  
U. L�tz-Meindl
Keyword(s):  
Actin Filament ◽  
Filament System

scholarly journals Evolution of galaxies in groups in the Coma Supercluster

2020 ◽  
Vol 497 (1) ◽  
pp. 466-481
Author(s):  
Ruchika Seth ◽  
Somak Raychaudhury
Keyword(s):  
Star Formation ◽  
Kernel Density ◽  
Local Environment ◽  
Density Estimator ◽  
Intrinsic Properties ◽  
Filament System ◽  
Cluster Group ◽  
Star Formation Activity ◽  
The Galaxy

ABSTRACT We take a close look at the galaxies in the Coma Supercluster and assess the role of the environment (in the form of cluster, group, and supercluster filament) in their evolution, in particular, examining the role of groups. We characterize the groups according to intrinsic properties such as richness and halo mass, as well as their position in the supercluster and proximity to the two rich clusters, Abell 1656 (Coma) and Abell 1367. We devise a new way of characterizing the local environment using a kernel density estimator. We find that apart from the dominant effects of the galaxy mass, the effect of the environment on galaxies is a complex combination of the overdensities on various scales, which is characterized in terms of membership of groups, and also of the position of the galaxy on filaments and their proximity to the infall regions of clusters. Whether the gas can be turned into stars depends upon the level of pre-processing, which plays a role in how star formation is enhanced in a given environment. Our results are consistent with gas accreted in the cold mode from the filaments, being made available to enhance star formation. Finally, we show that the Abell 1367 end of the supercluster is in the process of assembly at present, leading to heightened star formation activity, in contrast with the Coma-end of the filament system.

scholarly journals Coalescence of Molecular Filaments

2020 ◽  
Author(s):  
Nanda Kumar ◽  
Doris Arzoumanian ◽  
Alexander Men'shchikov ◽  
Pedro Palmeirim ◽  
Shu-Ichiro Inutsuka
Keyword(s):  
Surface Density ◽  
Unit Length ◽  
Radial Profile ◽  
Equal Mass ◽  
Star Forming ◽  
Filament System ◽  
Density Maps ◽  
Wide Range ◽  
Diffuse Cloud ◽  
Order Of Magnitude

Abstract Star-forming molecular filaments are found to display a spectrum of line-masses (mass per unit length)1. This spectrum is thought to influence key observational parameters of star formation2 including the core and stellar initial mass function1. The exact mechanism producing the wide-range of line-masses is unknown, even though, higher surface densities are often observed at the intersection of filaments in hub-filament systems3. Here we show that cascades of lower density filaments coalescing to form higher density filaments and eventually hubs. By performing a multi-scale decomposition of surface density maps of the MonR2 star-forming region, which displays a spiral-shaped hub-filament system4, the coalescence effect is detected in two consecutive cascading steps (the surface density jumps by an order of magnitude at each step) before merging at the central hub which is found to be a dense network of short high-density filaments (as opposed to its view as a massive clump). The radial density structure of the dense-gas component of the hub-filament system shows a power-law dependence of NH2 ∝ r−2 over the scale of ∼5 pc, a feature previously found only at scales of 0.1 pc in star-forming cores5. It appears that the hub-filament system is mimicking the radial profile of an isothermal sphere, at parsec scales, a feature not known until now. This behavior is not seen for the diffuse cloud (NH2 ∝ r−0.5) which holds nearly equal mass. The filamentary nature of the hub implies that only some (embedded in the filaments), and not all, stellar seeds within the hub can become massive stars.

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